When is one hit too many?

Purdue researchers are examining subconcussive injury in football players.

The suicide of former NFL middle linebacker Junior Seau focused renewed attention on the problem of brain injuries in football. On June 7, a "master complaint" was filed by more than 2,000 former NFL players and their families alleging that the NFL has ignored scientific research showing a direct correlation between football and brain injury.

Ongoing Purdue research into football players' brains bolsters one element of the lawsuit against the league: Repetitive blows to the head produce subconcussive injury and increase the risk of long-term brain damage and cognitive decline.

The Purdue Neurotrauma Group (PNG) gained national attention in 2010 for its work in studying the brains of high school players. But the research, which first focused on the effects of concussions, now shows something even more disturbing: More than half the players who never suffered concussions experienced neurophysiological changes to their brain that often affects cognitive abilities. This was determined using functional magnetic resonance imaging (fMRI).

Do football helmets help much to prevent brain damage?

"I don't know what the NFL said or didn't say to its players, but fMRI exams repeatedly tell the truth: Repeated blows to players' heads change the way the brains function for the worse," says Tom Talavage, professor of biomedical engineering and a principal investigator. "We may be putting too much focus on concussions. That is only the final straw after thousands of hits over several years."

Early research was featured in Sports Illustrated, "NBC Nightly News," CNN and PBS' "Frontline." Over three seasons the researchers have used sensors in helmets to document blows to the head. Players take cognitive exams and fMRIs before, during and after the season.

A high school football player may take anywhere from 200 to 1,800 hits to the head during the course of a single season. The researchers have uncovered data contradicting the classic idea that the concussion a player receives in November is completely unrelated to anything that may have happened in August or September.

"What we're finding is that you can get a concussion from a single blow, but if you take a whole bunch of blows before that, the concussion will probably be a lot worse," says Eric Nauman, professor of biomedical engineering and a PNG co-investigator.

"Just trying to get rid of the big hits isn't going to solve the problem."
– Ed Breedlove

Findings could aid efforts to develop safety guidelines that stipulate the number of hits a high school player should receive and may help determine techniques that coaches and players might use to reduce the severity of blows to the head. The work has also led to the development of new shock-absorbing materials for football and the military.

Purdue will also be collaborating with the Big Ten Conference and the Ivy League on a major, co-sponsored research partnership to examine and address concussions and other head injuries among athletes. Combined the Big Ten and Ivy League have more than 17,500 athletes. The initiative, announced June 19, is part of the Committee on Institutional Cooperation, the Big Ten's internal academic association.

New helmet technologies to reduce G-force transfer to the brain

The researchers have been consulting with high school and college athletic associations to improve safety through better coaching and officiating. They have also developed new helmet technologies that dramatically reduce the G-force transferred to the brain.

"Football helmets are designed to protect the skull and the face, not the brain," says Nauman. "We can build a better helmet, but we are probably going to have to find ways to reduce the number of times boys and young men subject their brains to massive G-forces."

"We may be putting too much focus on concussions."
– Tom Talavage

New football helmet interior padding has been developed using silicone-based material. Talavage says that when you push it in, it continues to give more than the rigid pads currently used.

In an interview with Indianapolis NBC affiliate WTHR-13, Talavage said that the padding "acts as a crumple zone of a car. Your car collapses and in general your passenger compartment remains relatively intact."

Nauman says that improvements could also come to the helmet's outside material too, adding, "Anytime you can get it to flex or deform without doing damage to the helmet, it will absorb energy and transfer less energy to the skull or brain."

Using brain-imaging technology to reveal changes

Researchers at PNG are using a type of brain imaging technology called functional magnetic resonance imaging, or fMRI, along with a computer-based neurocognitive screening test. The fMRI scans reveal which parts of the brain are most active during specific tasks.

Talavage says the scans have indicated that players are adapting their mental processes to deal with brain changes.

"The changes in brain activity that we are observing suggest that a player is having to use a different strategy to perform a task, and that is likely because functional capacity is reduced," Talavage says. "The level of change in the fMRI signal is significantly correlated to the number and distribution of hits that a player takes."

Though performance doesn't change, Talavage says, brain activity does, "showing that certain areas are no longer being recruited to perform a task."

The team wants to increase the number of football players in the study and include soccer athletes, who don't wear head protection, Nauman says. "We also want to include girls to see whether they are affected differently from boys."

Evan Breedlove, a graduate fellow in mechanical engineering, is part of the PNG research team. He says that findings have shown that it's the whole set of hits a player takes that lead up to the final one that "breaks the camel's back."

"Just trying to get rid of the big hits isn't going to solve the problem."